1. Field of the Invention
The invention relates to exchanging multimedia content and other digital information between a mobile communication device and a local or private network, including network devices belonging to the local network. More particularly, the invention relates to providing network connection establishment using a local network address for a device that is not connected to the local network and mobility for a mobile communication device across networks, such as from a private or local network to an external or public network.
2. Description of the Related Art
Many network communication devices, including mobile (handheld) communication devices, are configured to operate within a network structure according to home networking protocols, such as a set of guidelines established by the Digital Living Network Alliance (DLNA) or the Open Mobile Alliance (OMA). For instance, the DLNA guidelines were established to facilitate the interoperability of consumer electronics (CE) devices (e.g., set-top boxes), personal computer (PC) and other Internet devices, and mobile devices (e.g., mobile phones and personal digital assistants). The DLNA guidelines include protocols that support many computer and Internet-based protocols, including universal plug and play (UPnP™), which is a set of computer network protocols aimed at providing relatively seamless connection between devices, such as within one or more networks. DLNA (or DLNA/UPnP) devices typically are connected to or communicate with a local or private network, since many of the protocols supported by the DLNA work only in a local or private network arrangement. Therefore, when a mobile communication device, such as a mobile DLNA or mobile DLNA/UPnP device, leaves its local network, the mobile communication device no longer is able to communicate with its local network or any of the participating network elements and devices that also are part of the local network.
Conventional methods exist that allow for mobile communication devices, such as UPnP devices or DLNA/UPnP devices, access a local network even when the mobile communication device leaves or loses contact with the local network. One conventional method involves the use of a UPnP bridge between a first local UPnP network and a second UPnP network. This method assumes that the IP addresses in the first and second network are routable in each others domain. The UPnP bridge captures all of the UPnP packets, sent to a standard SSDP port, at the location of the first network, repackages the packets, and sends the repackaged packets to the location of the second network via the Internet. Although the method uses a relatively simple design, it is not applicable to private IP addresses (such as addresses behind a Network Address Translator (NAT)), which are typical of home networks and hotspots. In such conventional methods, such private addresses are routable only in a single local network. Also it does not handle establishing and continuing a session when a device is not connected to a local network or changes IP addresses.
Another conventional method involves the use of a connection-based protocol that is not restricted to a local network, such as Session Initiation Protocol (SIP), between a mobile device connected to a wide area network (WAN) and a controller in the home network. The controller translates messages received via SIP to UPnP and then uses UPnP inside the home network to enable the mobile device access the UPnP devices inside the home network. However, such translations are process intensive and offer only a relatively limited set of features.
Despite these existing methods and systems, there is a need for allowing a mobile communication device, such as a DLNA or DLNA/UPnP mobile communication device, to continue communicating with its local network even when the mobile communication device loses contact with and/or travels beyond the coverage area of its local network.